Fix the cost unit first
A cost estimate is only comparable if it is expressed per unit of work: per car, per bay-hour, per shift, per square metre of floor. Decide the unit before you price anything, because a machine that looks cheap per machine can be the most expensive per car once labour, waiting and re-work are added. For a wash bay the honest unit is total cost per completed vehicle, not the price of the equipment divided by its life.
Cost the labour, which is usually the largest number
Time one complete job with one operator and stop the clock at each stage: move-in, pre-rinse, steam pass, interior work, engine compartment where it is part of the service, and move-out. Repeat it five times and use the average, because the first run always flatters the process. Multiply by the wage cost including the time the operator spends waiting for the machine to heat, to refill, or to recover from an empty tank. That waiting time is real cost, and it is the number a supplier's datasheet never shows you.
Cost the utilities and the consumables per job
PowerDe's Fixed Steam Cleaning Machine HW02 lists 6 kW heating power, a 160° steam temperature, 0.8 MPa vapour pressure and an 80 L tank on a 220 V supply, plus dry and wet steam modes and a vacuum function. Those figures let you compute the fixed-side cost per job: energy while heating and while working, and water drawn per vehicle against the tank size. Mobile units shift some of that cost into battery charging and charging time instead, which is why the PWD02 and HMW2 variants should be costed on their charge cycle, not on their catalogue name — and where the published page does not give battery capacity or run time, ask for it in writing before you estimate.
Cost the waste-water route, not just the cleaning
Greasy run-off has to leave the site, and the route it takes is a cost. On a forecourt or in a workshop that means an interceptor or separator with a capacity, a service interval and a pump-out price. Estimate the volume your session generates against that capacity: if your cleaning plan will fill the separator faster than it can realistically be serviced, your real cost per car includes an unplanned pump-out. High-temperature steam removes grease with far less water, which is exactly why it lowers this line item as well as the drying time.
Add the fixed overheads you cannot avoid
Some cost is incurred whether you clean one car or a thousand: the installation (supply, plumbing, drainage, a charging point if the machine is battery-fed), the floor treatment and drainage falls, the training time, and the maintenance that keeps the warranty valid. Divide that overhead across your real annual volume, and the estimate changes completely if your volume is seasonal or if the bay is only partly occupied. A machine bought for a volume you do not have is the most common wash-bay cost mistake.
Compare options on the same sheet
Put each option — fixed machine, mobile battery machine, mobile mains machine — on one sheet with the same rows: labour minutes per car, energy per car, water per car, pump-out cost per car, amortised installation per car, and downtime per month. Then look at where each option wins. Fixed units usually win on heat and on continuous duty; mobile units win where the operator would otherwise spend time moving vehicles. That is also why PowerDe publishes the PWD02 range in two variants — the Driving Style Steam Cleaner PWD02 supplied without a battery and the version supplied with one — and the right choice depends on the sheet, not on the badge.
Review the estimate against what actually happens
After a month, replace your assumptions with the real numbers: jobs completed, labour hours logged, energy and water read from the meters, and every minute the bay was stopped. If the real cost per car is above the estimate, the cause is almost always waiting time or a stage that is being repeated. That is the point at which it is worth asking the supplier what changes — tank size, a second lance, a different steam setting — would move the number.
Getting the figures you need
Send your daily vehicle count, your available supply and your drainage situation to PowerDe through the contact page and ask for the run-time and consumption figures for the configuration that fits, with the numbers quoted explicitly rather than implied.
